Apparatus for straightening pipe



June 16, 1953 T. H. KENNEDY ETAL 2,642,113

APPARATUS FOR STRAIGHTENING PIPE Filed June 16, 1948 2 Sheets-Sheet 1Elli-i1 16 10b J 15 INVENTOR.

TRUMAN H. KENNEDY BY AND SAMUEL. WEBB a ATTORNE Y J1me 1953 T. H.KENNEDY ET AL 2,642,113

APPARATUS FOR STRAIGHTENING PIPE INVENTOR. TRUMAN H. KENNEDY AND SAMUELWEBB f owla /dd% ATTORNEY Patented June 16, 1953 .2; 3. 1..

7 2,642,113 I APPARATUS FOR STRAIGHTENING PIPE Truman H. Kennedy, E

gheny County, and

to United States Steel Cor- Hills,.Pa., assignors lizabeth Township,Alle- Samuel Webb, Pleasant poration, a corporation ofNew JerseyApplicationJune 16, 1948, Serial No. 33,358

' .2 Claims. (c1. 153-48) v This invention relates to the manufacture ofpipe and, in particular, to an apparatus for straightening pipe withoutsubjecting it to excessive cold work or introducing sufficient ovalityas to affect the physical properties, specifically the collapsestrength.

Seamless pipe as now produced is finally straightened cold, largely bypassing it through a straightener including spaced pairs of cross 7rolls and a bending roll therebetween. The

cross rolls rotate the pipe on its axis by friction and feed it axially.The forces applied may be great enough to cold work the pipe or producea slight degree of ovality therein which together materially affect thephysical properties, such as the collapse strength. 1 This seriouslyimpairs the quality of the pipe for certain uses, such as well casingwherethe maximum collapse strength is desired. In fact, straightening asnow performed largely wipes out the effect of certain processing stepsintended to, increase the collapse strength. As a result, a gag presshas been resorted to for straightening but this is a slow, tediousoperation requiring considerable skill.

We have invented a novel apparatus for straightening pipe whichovercomes the afore-v mentioned objections to the prior practice. Theobject of our invention is to provide an apparatus for straighteningpipe continuously at high speed without cold-working it enough to reduceits physical properties. 'A further object is to provide an apparatuswhich is simple and easy to operate and a-method which may be readilyintegrated into present mill procedure without introducing anydifficulty or slowing down production. In a preferred practice, weadvance the pipe axially while turning it on its own' axis and subjectit repeatedly to a momentary-transverse bending force applied inaccordance with a predetermined space-time relationship to the travel ofthe pipe. Specifically, weapply the force successively to points spacedsymmetrically I around the-circumference of the pipe, a predeterminednumber of times for a given axial travel of the pipe. -The apparatus weemploy is generally similar to the ordinary cross-roll straightener butincludes important features of novelty which adapt it for carrying outour method. We also bend the extreme ends of the pipe while theintermediate portion is held firmly gripped in order to remove hooks. Acomplete understandingof the invention may be obtained from thefollowing detailed description and explanation which. refer totheaccompanying drawingsrillustrating a preferred embodiment and practice.slnthe drawings,

the relative location of Figure l is a diagrammatic plan view showin thecross rolls for rotating and turning the pipe and the bending rollscooperating therewith;

Figure 2 is a similar plan view, likewise somewhat diagrammatic, showingmechanism for actuating the bending rolls into effective position andwithdrawing them therefrom, the main framework of the apparatus beingomitted;

Figure 3 is a transverse section on the plane of line III-III of Figure2, through the idler roll of one of the pairs of cross rolls;

Figures 4 and 5 are diagrams showing the distribution in lengths ofpipe. of two different sizes of the points at which bending force ismomentarily applied; and

Figure 6 is an end view of a modified form of bending roll.

Referring in detail to the drawings, and, for the present to Figure 1,spaced pairs of cross rolls in and Il, including driven rolls l0 and Hand idler rolls lo and H are disposed in the known manner so as torotate a pipe length P about its own axis by frictional contact and, atthe same time, feed it axially in the direction of the arrow, the crossrolls l0 being adjacent the entering end of the straightener and thecross rolls l l adjacent the exit end.

A bending roll I2 is mounted between the two pairs-of cross rolls formovement into and out of engagement with the pipe, as indicated by thepositions shown in dotted and solid lines, respectively. Hook-removingrolls [3 and M are similarly mounted adjacent the entrance and exit endsof the machine for temporary engagement with the extreme ends of alength of pipe, the roll 14 serving to engage the leading end of thelength. and the roll [3, the trailing end, when actuated to the dottedline position. It will be understood that the rolls of each pair I0 andH are skewed oppositely. The rolls [2, l3 andv M are likewise skewed inthe same direction as the idler rolls lo and H. The idler rolls, asshown in Figure 3, comprise a solid core 15 of metal having acontinuoussheath of rubber-like material It therearound. This sheath affords thefriction necessary to rotate the pipe without adjusting the rolls ofeach pair to exert such pressure thereon as to introduce ovality intothe pipe.

Referring now to Figure 2 showing the means for driving the rolls IIIand H and adjusting the rolls l2, l3 and M in greater detail, it will benoted that a lineshaft I'l drives the roll W through bevel pinions l8.Similarly, the shaft 11 drives-the roll ,ll, through bevel pinions 30,

Guide shoes 2| and 22 are disposed between the rolls of each pair I andH. The idler rolls l and I I are journaled in bearing yokes 23 mountedin a suitable supporting frame for adjustment to and from the drivenrolls and l I with which they cooperate.

Each of the bending rolls l2, l3 and [4' is similarly journaled in a,bearing yoke 24 mounted for reciprocating movement toward and from theline of travel of the pipe P. Conveniently, the main supporting framemay be provided with ways (not shown) along which the yokes 24 areslidable. ward and away from the line of travelof the pipe by a pitman25 pivoted thereto and .to a crank 25. The bearing yokes 25 have spacedlugs 2'1 drilled to accommodate a wrist pin 28 which passes through thepitman 25. The .crank 26 is operated by a motor 29 having a built-ingear reducer 39. In Figure 2, the rolls l2, l3 and M are shown in theirretracted positions corresponding to the solid line positions ofFigure 1. They do not, therefore, engage a pipe length as the latter isintroduced first between the rolls l0 and 16 and then between the rollsH and H.

As soon as the entering pipe length is frictionally engaged by the rollsIll and [9 of course. it is rotated about its own axis and fed axiallyover the guides 2| and 22. When the leading end has been engaged bytherolls ll" and l 1 the motor 29 actuating the roll I2 is started.Continuous operation of the motorcauses a bending force to b applied atspaced intervals transversely of the. pipe between the rolls Hi and I lwhich constitute abutments aifording the necessary reaction to thebending force exerted by the r011 12. The motor 29 operates continuouslywhile the pipe length is traversing the machine and' thus exerts itsbending force momentarily at points spaced circumferentially andlongitudinally of the length, once for each revolution of crank 26.

We have found that, for good results, the points at which bending forceis applied should. be symmetrically spaced circumferentially of thepipe. In addition, the force should be applied to a complete series ofthree, four or six points about the circumference in each successivefour-foot portion of the length or thereabout. This may be bestexplained by reference to Figures 4 and 5. Figure 4 shows the locationof four points, a, b, c and d, at which the bending pressure is appliedto a 4 0. D. pipe-in a 3' 10" length thereof. It will be observed thatthe points'are spaced 90 apart around the circumference of the pipe.They are spaced apart longitudinally about 2%; revolutions of the pipewhich travels 3' 10" in the nine revolutions required to complete theentire cycle of four applications of vbendingpressure. 7

Figure 5 demonstrates a similar but somewhat altered practice applicableto 8%" O. D. pipe. Here the points of successive application of thebending pressure are designated, as in Figure i, and are spaced 90 apartcircumferentially of the pipe. Because of the larger size 'of the pipe,however, only five revolutions thereof are necessary to move the pipeaxially the distance covered by a complete cycle which comes out 4 1".The points of application of the bending pressure may be 60 or 120apart, instead of 90. There would then be six or three points ofapplication in each approximate four-foot portion of the pipe length.

The actuation of the roll [2 toward and from Each bearing yoke isactuated to the pipe to apply bending pressure at points spaced apart bythe desired angles circumferentially and the desired distancelongitudinally may easily be controlled by varying the speed of motor 29so as to correlate it with the rotation of thepipe and its axial travel.The rotation of the pipe, of course, depends on the speed at which therolls Ill and ll are driven and the axial travel of the pipe depends onthe angle of skew at which the rolls of each pair [0 and I I are setrelative to each other.

As theleading end of the pipe length emerges from betweenthe rolls ofpair II, the bending roll 14 is advanced into operating position byenergizingits motor 29. In case the pipe length has ahook at the end,which is the usual condition, engagement thereof by the roll M as thepipe rotates and the hooked end oscillates about the mathematical axis,straightens the bent portion and leaves it accurately aligned with theintermediate portion. The roll I4 is left in its advanced position onlywhile the first eight inches or so of the pipe length are traveling pastit, after which the roll is retracted and remains out of the Way untilthe leading end of the succeeding length approaches.

' The roll I3 is actuated in precisely the same manner to straighten thetrailing end of the pipe length by removing any hook therefrom. In

other words, the roll I3 is advanced into engagement with the pipe at apoint about eight inches from itsextreme trailing end and is retractedwhen the end has passed. The engagement of the rolls [3 and M with thepipe is continuous and not intermittent, as in the case of the roll I2.Instead of employing the crank and pitman for advancing and-retracting.the bending rolls, we may employ any equivalent'mechanical device, suchas cams, toggles or hydraulic cylinders. Instead of bodily advancing andretracting the bending roll l2, we may employ an eccentric roll or aroll having an eccentric or built-up portion at one point onitsperiphery. Either of these expedients serves in the same manner asalready explained to exert bending pressure on the pipe at points spacedcircumferentially and longitudinally as it rotates and travels axiallythrough the machine. Figure 6 shows a bending roll IZT having a shaft 3|which is eccentric relative to the body thereof.

' We have found that, by causing the bending roll l2 to engage the pipeintermittently, the pressure which must necessarily be exerted by thecross rolls on the pipe to rotate it by frictional engagement is not sogreat as to effect coldworking or introduce ovality into the pipe tosuch extent as to impair its physical properties. This result is alsoaided by the use of rubber sleeves on the idler rolls "l and liThe'invention thus permits pipe to be straightened as rapidly as ispossible with a conventional straightener, without reducing its physicalproperties, such as collapse strength, whichhas been a. necessaryconcomitant of the. use of conventional straighteningmachines. Inaddition, we are able to remove hooked ends which are frequentlyencountered, thus leaving the pipe precisely straight throughout itsentire length. The method of .our inven-" tion may readily be integratedwith the conventional procedure formaking seamless tubing continuously,without increasing the difiiculty .thereof or slowing down production..JOur apparatus,

furthermore, involves only a slight increase over.

the cost of a conventional straightener and its 5 operation does notrequire any more skill than the latter.

Although we have illustrated and described but a preferred embodimentand practice of our invention, it will be recognized that changes in thedetails and procedure disclosed may be made without departing from thespirit of the invention or the scope of the appended claims,

We claim:

1. In a pipe straightener, two pairs of cross rolls in tandem adapted toturn a pipe on its axis while advancing it axially therebetween, abending roll between said pairs of cross rolls and skewed similarly toone of the latter, a second bending roll beyond one pair of cross rollsand means for continuously advancing the bending rolls into engagementwith the pipe and retracting them therefrom at a predeterminedfrequency.

2. In a pipe straightener, two pairs of cross rolls in tandem adapted toturn a pipe on its axis 20 while advancing it axially therebetween, abending roll between said pairs of cross rolls and skewed similarly toone of the latteryand means for continuously advancing the bending rollinto engagement with the pipe and retracting it therefrom at apredetermined frequency.

TRUMAN H. KENNEDY. SAMUEL WEBB.

References Cited in the file 01 this patent UNITED STATES PATENTS Number15 Number r 29,023 303,790 38,779 507,933

Name Date Robertson Mar. 31, 1874 McCool Jan. 1, 1889 Muncaster Oct. 3,1899 Muncaster Oct. 1, 1912 Sleeper Apr. 3, 1917 Wise May 12, 1931Hartley Nov 1'7, 1931 Urschel Apr. 26, 1938 Huston Sept. 20, 1938FOREIGN PATENTS Country Date Germany Oct. 21, 1884 Germany Feb. 15, 1918Switzerland Apr. 1, 1921 Germany Sept. 22, 1930

